As you grab your favorite fleece -- again -- and curse management for banning space heaters, the answer might be easy ... until you look around. As your teeth chatter uncontrollably, the person sitting next to you is typing away, comfortable as can be, in short sleeves.

Glenn Friedman, principal at Taylor Engineering, a Florida-based mechanical design firm, estimates that 72 degrees is a middle-range comfort level for the workplace. A Cornell University study found the optimal office temperature to be about 77 degrees.

But even in offices with optimal thermostats, studies have shown that some employees will still be unhappy.

"If you take the average office environment and you interview people, you'll find about 80 percent of people in a 'comfort range' are comfortable," Friedman says.

This leaves workers facing a baffling question: How can some people in an office feel too hot, and others too cold, when they're sitting right next to each other?

Science behind temperature

Human brains have a thermostat center in the hypothalamus at the base of the brain where automatic body function and regulation takes place, according to Georgianna Donadio, a Boston, Massachusetts, educator and health care provider.

The thyroid gland regulates the body's metabolism. For example, when it is cold outside, the skin registers the change in temperature and stimulates the hypothalamus and thyroid to increase metabolism and create more heat.

But people do not always regulate body temperature in the same say, Donadio says.

Dr. Vicki Rackner, author of "Chicken Soup for the Soul Healthy Living Series: Heart Disease," says some variation in perceived temperature is normal. "Unique biological differences cause every person to have a unique ideal temperature," she says. "We each have a thumbprint about where we thrive."

Donadio says a multitude of factors can cause an otherwise healthy person to feel warmer or colder than his or her peers. "The reason why a person is cold is very individual and unique to that person," she says.

Among the factors:

Weight: "The more body fat you have, the more insulation you have, so you tend not to be as cold generally," Donadio says.

Fitness: The amount of dense muscle an individual has helps the body regulate temperature more efficiently, Donadio says. "There's no question," she says, "that if you want to enhance the overall regulation of your system -- exercise. It's scientifically proven that it's the single most important thing anyone can do for themselves, ever."

Diet: People who do not get enough vitamins, minerals, protein, vegetables and other essential nutrients for a healthy metabolism could find themselves feeling tired and cold because their metabolism is not getting the nutrients it needs to work efficiently, Donadio says.

Gender: Women are more prone to hypothyroidism than men are, according to Donadio. Hypothyroidism is a condition in which the thyroid works too little and causes the patient to feel cold. Women's body temperatures are also prone to irregularity due to their menstrual cycles and menopause, and women generally have less dense muscle mass than men do, which lowers their average body temperature.

Age: According to Donadio, as people age, their hormonal systems may begin to function differently. When they do not produce as many hormones as they once did, they may find themselves feeling colder. Likewise, hormonal surges associated with menopause can cause hot flashes.

Stress: Being too tense or uptight in the office could reduce your circulation, making you feel colder, Donadio says.

Staying comfortable

If you find your office is unbearably hot or cold, don't head immediately to the doctor, Donadio says. Instead, first try some personal reflection.

"If we listen to our bodies, our intuition, we can know why they're not warm or able to adapt to our environment -- and we know what's causing it," she says.

But if there is a sudden or dramatic change in your body temperature, it may signal something more serious, such as a thyroid problem, Rackner says.

"People who always have to wear more layers, for their whole life -- that's probably just who they are," she says. "If they suddenly find they need four more layers, that may mean it's time to go in and see the doctor."